This invention relates to message boards and more particularly to message boards for displaying interchangeable messages made up of alphanumeric character bearing strips.
Prior art message boards hve included device for mounting changeable, alphanumeric character bearing elements. A cover plate has been attached to such devices in engagement with the front surface of the character bearing element to prevent their displacement. Frictional force to hold the characters in position was provided by mounting the cover upon the device with fastening screws, for example.
One disadvantage in message boards of this type has been that the device was required to be removed from any support and laid flat, parallel with the ground, when a message was set up or changed. Otherwise, without the support of the cover, which was removed, the alphanumeric character bearing elements would fall to the ground. No frictional holding forces were applied until the cover was secured to the device. Therefore, every change of the message necessitated a dismounting of the back plate and a disassembly of the cover.
Other prior displays alleviated the inconvenience of dismounting the back plate each time that the message was changed by adding a trough recessed within the back plate. This trough provided a ledge or opening for mounting elements thereon.
The use of troughs, however, was insufficient to prevent character element displacement when these message display devices were attached to moving or vibrating surfaces, such as to vehicles. Falling and sliding of character elements out of place continued to occur with any message device not used in a stationary application.
Another solution to the problem of displaced character elements was to provide key holes in the back plate and characters with pegs projecting rearwardly for insertion into these key holes. The snug fit of the alphanumeric characters into these key holes prevented displacement of the characters.
Nevertheless, a disadvantage in message boards of this type was the space required for storing these alphanumeric characters. Character elements having rearwardly projecting pegs were bulky and not easily stored. Since the variety of messages which may be displayed is directly proportional to the available supply of a number of alphanumeric character elements, more convenient storage of character elements has been desirable to provide a greater number of easily stored elements to allow greater message variety.
Another type of prior message device included a cover plate hinged to the device at an edge thereof. Such devices were popular for use in trinkets or key chains and the like. Grooves were placed in the trough to slidably receive character elements. This required an entire character element line to be slidably mounted within the message board in the correct sequence. The hinged cover also required additional attachments or snaps to secure the cover onto the device.
Message boards of these types, when used outdoors, are subject to leakage, weather intrusion and difficulties in message adjustment or changes. Gaps necessary to provide a minimum clearance distance to allow free hinging of the cover allow seepages of moisture between the face plate and the back plate. This moisture obscures messages and subjects the character strips to additional wear and tear. Moreover, such devices are typically mounted for stationary use and does not provide for suitable character element security against displacement when subjected to vibrations or movement such as generated by a vehicle.
It is therefore an object of this invention to provide a message board in which alphanumeric character strips are securely disposed against movement due to vibration of the board.
It is another object of this invention to provide a message board which does not require dismounting of the board from a support in order to change the alphanumeric characters, but wherein the message can be changed with the board in vertical disposition.
It is yet another object of this invention to provide a message board together with securably mountable, readily storable, flat character bearing elements.